The art is replete with structures for sheets adapted to mark portions of substrates such as written documents, and dispenser packages for such sheets. Sheets from Post-it brand note pads available from Minnesota Mining and Manufacturing Company are used extensively as such sheets, and are particularly useful for that purpose because a repositionable pressure sensitive adhesive with which they are coated allows them to be placed on and removed from a document without damage to the document. Such sheets are not as suitable for marking portions of substrates as may be desired, however, because relatively small percentages of such sheets are coated with the repositionable pressure sensitive adhesive so that they are sometimes dislodged during handling; because the sheets are made of paper and easily become damaged, and because the sheets are opaque so that they obscure more of the document they are marking than may be desired.